This is for people who mostly use chat AI and are only now trying to follow new AI tools. You see another AI app post, almost scroll past, then stop because you do not want to miss the one detail that changes your next move. Here it is: for a first version, route.ts, actions.ts, and policy.sql can be enough. Those three files can be enough for the first working version [C001].
The wrong beginner question is still: "Ask an AI expert: What exactly is the full stack?" That question sounds serious, but it often points beginners at the wrong setup first. If you only follow the surface hype, you can burn time, budget, and attention on setup before you prove the product does one useful thing. The hidden cost is that you keep learning labels instead of making a working first pass.
The docs-based version is smaller. route.ts is the entry point: Next.js route files can handle the request and response directly. actions.ts is the server-side step: Next.js Server Actions let a client trigger work that still runs on the server. policy.sql is the access rule: Supabase says browser access is safe only when Row Level Security is enabled, and with RLS on, no policy means no data access even with a public key [C001]. For v1, that is often the real full stack: one way in, one server step, one rule around data.
This is not a claim about every production app. It is a boundary: a first version using Next.js + Supabase docs is not the same thing as a mature system. But that boundary is the useful part. Do not judge an update by how many features it lists. Judge it by whether it changes your next decision. If you know someone stuck on the idea that AI full stack must start huge, share this with them.